图解肩袖检查.doc

Examination of the rotator cuff
SJ Drew and RJ Emery 
Figure 1: Palpation of the bulk of the infraspinatus muscle.

Figure 2: Palpation for a defect in the superior aspect of the rotator cuff.

Figure 3: The lift-off test of Gerber, with the addition of the application of resistance.

Figure 4: Demonstration of a positive internal rotation lag sign where the patient is unable to actively maintain the hand held backwards off the back.

Figure 5: The belly press test. The patient is unable to prevent the humerus and elbow falling back into extension because of a subscapularis tear.

Figure 6: An inability to resist the examiners downward pressure because of a tear of the supraspinatus.

Figure 7: An inability to resist an internal rotation force because of a tear of the posterior cuff (infraspinatus and teres minor).

Figures 8 & 9: The patients arm is passively taken into maximal external rotation (figure 8) and asked to maintain this position when the examiner lets go of the arm. An inability to maintain this position so that the arm swings back towards the neutral position demonstrates a positive external rotation lag sign (figure 9).

Figure 10: A positive hornblowers sign on the right.

Whilst the expansion and improvement in imaging techniques most notably ultrasound and MRI has undoubtedly improved our understanding of rotator cuff pathology the management of rotator cuff tears can be based almost entirely on clinical findings.
The aims of the clinical examination especially when one is considering operative intervention are to determine:
1) That the shoulder is not stiff
2) The source of the pain. This may arise from a variety of sources including; Subacromial inflammation/bursitis, mechanical impingement, fatigue (pain experienced on activity from a weak easily fatigued muscle) and intrinsic cuff pathology.
3) The site of the rotator cuff tear. It is particularly important to determine if there is a subscapularis tear since this would not be easily accessible via a standard approach used for cuff surgery such as a deltoid split.
4)  The size of the rotator cuff tear. If the tear is very large as demonstrated as will be discussed later by the presence of lag signs, then it may not be possible to surgically repair the tear. A muscle transfer such as a Latissimus dorsi transfer should be considered in these situations in which case the patient would need to be positioned in the lateral position.
5) The presence of fatty degeneration most notably in teres minor. The presence of fatty degeneration may well influence ones decision to operate since fatty degeneration of the motor unit tends to preclude a good result from surgical repair.
There are a vast number of clinical signs of rotator cuff tears that can be very elegantly demonstrated (and often are at clinical meetings) but how many of these signs are really useful or bear much resemblance to clinical practice? If the test or sign has not been validated it should be treated with a healthy degree of scepticism. The purpose of this paper is to identify those signs we feel are useful in clinical practise i.e. what we look for in the clinic when faced with a patient with a possible rotator cuff tear.
Wasting of the motor unit is an important sign that can be both observed and palpated. It is important to determine if the wasting is global, involving the whole of the shoulder girdle musculature or isolated to the spinati. The bulk of trapezius should be noted, as should the presence of any ptosis of the shoulder. Wasting of the infraspinatus is easier to observe than wasting of supraspinatus because of the presence of the overlying trapezius muscle, which may mask supraspinatus wasting. We therefore feel that a better idea of muscle bulk can often be obtained by palpation of both spinati in the supraspinatous and infraspinatous fossa respectively (figure 1).
A finger placed over the antero-superior aspect of the humeral head can usually palpate a defect in the superior aspect of the cuff such as the leading edge of supraspinatus, which is a very common site for a tear (figure 2).
However, since the wideness of the rotator interval is variable, as is the amount of cover afforded by the acromium, the arm should be taken into 30-40o of abduction and then externally and internally rotated. The defect can often be palpated under the finger together with the presence of crepitus. If the leading edge of supraspinatus is intact and the cuff tear is behind it then the defect may be more difficult to feel. The posterior aspect of the cuff is hidden underneath the acromium so is far less accessible. Extension and external rotation will bring a variable amount (dependent on the amount of cover from the acromium) of the posterior aspect of the cuff far enough forward to be palpated.
Palpation more medially between the coracoid process and the long head of biceps with the glenohumeral joint taken into extension and external rotation may produce tenderness if there is a tear of the subscapularis tendon. However, more reliable signs of a subscapularis tear include the lift off-test of Gerber and the belly press test.
The lift-off test was described by Gerber and Krushell and is a specific test for subscapularis. It is performed by having the patient maximally internally rotate the shoulder and place the back of the hand behind the back at waist level. The patient is then asked to lift the hand backward off the back. This manoeuvre is then repeated with the addition of resistance from the examiner’s hand to assess the degree of power (figure 3).
The final component of this test is the presence or absence of an internal rotation lag sign. For this the patient again places the back of the hand behind the back and the examiner then passively lifts the hand backward off the back. The patient is then asked to maintain the hand in this position when the examiner lets go of the hand. The lag sign is positive if the patient is unable to maintain the hand in this position and it falls forward onto the back (figure 4).
In assessment of the subscapularis, Hertel et al.1996, have shown that the internal rotation lag sign is as specific but more sensitive than the lift-off sign. Partial ruptures of the subscapularis could be missed by the lift-off sign but were detected by the internal rotation lag sign. The magnitude of the lag correlates well with the size of the defect. The belly press test is also useful for assessing subscapularis function particularly in the situation where there is insufficient internal rotation to allow performance of the lift-off test. In this test the patient places the palm of the hand on the abdomen and is asked to push the hand against the abdomen. They should be able to do this whilst maintaining the humerus and elbow level with the trunk. If there is a defect in the suscapularis the humerus and elbow will fall back into extension (figure 5). Our own experience very much mirrors these findings and we would stress the importance of determining the presence of a subscapularis tear as this has a critical bearing on the prognosis.
When testing the strength of supraspinatus and infraspinatus it is difficult to entirely isolate these two muscles and the tests performed are inevitably a combination of both muscles. However the strength of supraspinatus we have found is best assessed by the following test usually ascribed to Jobe. The patient is asked to place both arms in 90o abduction in the plane of the scapula (about 30o flexion). They are asked to resist downward pressure exerted by the examiner's hand placed on the patient’s forearm just proximal to the wrist.
Initially they are asked to resist with the thumb pointing cranially (external rotation) and then supraspinatus is isolated by internally rotating so the thumb faces the floor. An inability to resist the examiners downward pressure when the thumb is pointing down is a sign of a defect in the superior aspect of the cuff involving supraspinatus (figure 6).
Assessing the strength of external rotation is a combined test of supraspinatus and infraspinatus function. Initially this is assessed with the arms held at the side and the elbow flexed to 90o. The patient is asked to resist an internal rotation force applied to both forearms by the examiners hand. This is then repeated with the arms held at 90o abduction and full external rotation (this is more specific for infraspinatus and teres minor). Again an internal rotation force is applied by the examiner's hand. Inability to resist the examiners hand in this second test is one of  the so-called ‘dropping’ signs as described by Hertel (1996) and is similar to a hornblower’s sign. (figure 7).
The external rotation lag sign is a combined test for supraspinatus and infraspinatus. In this test the patient with the arm at the side and the elbow flexed to 90o has the arm taken passively into maximal external rotation (figure 8).
They are then asked to maintain this position when the examiner lets go of the arm. An inability to maintain this position so that the arm rotates back towards the neutral position is a positive external rotation lag sign (figure 9).
The Hornblower’s sign is a sensitive and specific test of teres minor function which is often overlooked in rotator cuff injuries despite evidence that it contributes up to 45% of the power of external rotation. The patient is asked to put the hand to the mouth as if blowing a horn with the elbow held at the same level as the hand. The patient is then asked to extend the arm at the elbow at the same time taking it into external rotation. A positive test occurs when the patient is unable to externally rotate the arm from this position (figure 10).
Another way to demonstrate the hornblower’s sign and the method that was originally reported (Arthuis, 1971) is to ask the patient to bring both hands up to the mouth. If the hornblower’s sign is positive the patient is unable to do this without abducting the affected arm and demonstrates the difficulty in raising the hand to the mouth in the absence of external rotation of the shoulder. In the presence of a combined supraspinatus and infraspinatus tear, an intact, or even hypertrophied teres minor can contribute enough power to external rotation to prevent the hornblower’s sign being positive. This demonstrates the importance of teres minor in maintaining the ability to perform the activities of daily living involving external rotation of the shoulder (hand to mouth, hand to head etc.). 
The dropping sign, hornblower’s sign, Jobe sign and external rotation lag sign have been validated in two studies. Walch et al, 1998 showed that the hornblower’s sign had 100% sensitivity and 93% specificity for irreparable degeneration of teres minor and the dropping sign (as originally described by Neer and analogous to the external rotation lag sign) 100% sensitivity and 100% specificity for similar degeneration of infraspinatus. These clinical signs were correlated with operative and MRI findings. These signs indicate irrecoverable degeneration in teres minor and infraspinatus respectively which will have a 50% re-rupture rate after surgical repair and should serve as a warning sign to surgeons when considering repair, a conclusion which we can only endorse from our own experience.
Hertel et al, 1996 evaluated the dropping sign, the Jobe sign and the external rotation lag sign. They found that for the assessment of supraspinatus and infraspinatus the external rotation lag sign was less sensitive but more specific than the Jobe sign and that the dropping sign was the least sensitive but as specific as the external rotation lag sign. The external rotation lag sign would not detect partial tears of the supraspinatus. Again the magnitude of the lag correlated well with the size of the defect in the rotator cuff. We have found the external rotation lag sign and the hornblower’s sign especially helpful in determining the presence of a large cuff tear and its prognosis for surgical repair.    
When observing both resisted external rotation and resisted abduction it is important to observe what happens to the humeral head. In sizeable cuff tears the humeral head will tend to ride up anterosuperiorly on commencing the active movement.
Defects in the cuff may also produce coracoid impingement where because of the anterosuperior migration of the head, the anterior cuff impinges between the humeral head and the coracoid process. This produces pain at the front of the shoulder especially during forward flexion and internal rotation. This is best demonstrated by the coracoid test usually used in determining isolated subscapularis tears, although there are other idiopathic and iatrogenic causes. In this test, the pain is most reliably produced by internal rotation with the arm in 90o of abduction, or by adduction with the shoulder flexed to 90o (Gerber et al, 1985).
The presence of stiffness is a poor prognostic sign and should be actively sort. We have found that the amount of passive flexion and external rotation are both best determined by lying the patient flat on the couch. Determining the maximum spinal level to which the thumb or index finger can be raised with the arm behind the back can quickly assess internal rotation. However, passive internal can also be tested using the transcondylar axis either, with the arm held by the side or by lying the patient on their front. We have not found that either of these manoeuvres adds much to our findings. The cross arm adduction test where the arm is adducted across the chest in successively higher degrees of flexion is useful in determining the tightness of the posterior capsule. If the posterior capsule is tight then the amount of adduction will reduce as the arm is placed in higher amounts of flexion. However it should be noted that in higher amounts of flexion this test also becomes an impingement test so if pain is present on using this test the result should be interpreted with caution. 
When observing movements of the glenohumeral joint it is vital to observe the patient from behind to assess scapulothoracic rhythm. This should be smooth and symmetrical on both sides. Patients with cuff tears often develop a ‘hitching’ action to compensate for weakness of abduction and this is readily visible from behind.
In younger patients, often manual labourers or athletes it is possible to sustain a tear of the rotator interval. This is the wedge shaped region bounded by the subscapularis inferiorly, the supraspinatus superiorly, the hood over the bicipital groove laterally and containing the coracohumeral and superior glenohumeral ligaments. On initial examination there may be few signs of a rotator cuff tear, however, the classic sign of a rotator interval tear is increasing weakness on repeated testing of resisted abduction. Initially the strength of resist